Need help debugging jscript event that shows/hides sections based on Opportunity Scope field

I am trying to use a jscript event to show/hide tabs on my Opportunity form based on what is selected in the "Opportunity Scope".  I have made this an OnLoad event, as well as an "OnChange" event for when the Opportunity Scope field is changed.  However, I haven't been able to get the event to work.  I am fairly new to javascript and could use some help debugging.

Here is my code:

function HideShowOpportunityTabs()
{
OppScope = Xrm.Page.getAttribute(“new_OpportunityScope”);
if (OppScope.getValue() != null)
{
if(OppScope.getText()==”Product”)
{
Xrm.Page.ui.tabs.get(“RecurringRevenue”).setVisible(false);
Xrm.Page.ui.tabs.get(“FieldService”).setVisible(false);
}
else if (OppScope.getText()==”Professional Services”)
{
Xrm.Page.ui.tabs.get(“RecurringRevenue”).setVisible(true);
Xrm.Page.ui.tabs.get(“FieldService”).setVisible(true);
}
}
}

When I load the form, I receive the following error:

The "OnChange" event is not working either.  It does not cause an error, but the sections are not being hidden.

Any help fixing this would be greatly appreciated.  Thanks!